In recent years, machining using an end mill or other milling tool has been made highly automated by numerical control, computer control, and other techniques. Such an automated machine tool is operated in accordance with a processing program in which path information of the tool, processing conditions of the workpiece, etc. are coded. Further, due to shape data of workpieces prepared by a CAD (Computer Aided Design) system, CAM (Computer Aided Manufacturing) systems which enable a processing program to be automatically prepared have been spreading. A CAM system receives as input not only shape data of a workpiece which is output from the CAD system, but also various types of information relating to the tools, workpieces, etc. so as to automatically generate a processing program including the toolpath.
Japanese Unexamined Patent Publication No. 2007-257182A discloses a method of calculation for calculating an amount of interference of a milling tool penetrating inside a workpiece in virtual profile machining using a computer.